Question 365551
Hi, 
Let x represent the amount of money Julio invested.
then Krista invested (x-$200)
{{{.06*x = I[J]}}}
{{{.09(x-200) = I[K]}}}
.09(x-200) - .06x 
.03x  - 18 = difference between the amount of interest krista had earned and the amount julio had earned